The present application relates generally to an improved apparatus and method and more specifically to mechanisms for sacrificial carrier dicing of semiconductor wafers.
In electronics, a wafer, which may also be referred to as a slice or substrate, is a thin slice of semiconductor material, such as a silicon crystal, used in the fabrication of integrated circuits and other microelectronic devices. The wafer serves as the substrate for microelectronic devices built in and over the wafer and undergoes many micro-fabrication processing steps such as doping or ion implantation, etching, deposition of various materials, and photolithographic patterning. Finally, the individual microelectronic devices or chips are separated through a process referred to as wafer dicing. A chip in the context of integrated circuits is a small block of semiconducting material, on which a given microelectronic device or functional circuit is fabricated.
Wafer dicing is the process by which chips are separated from a wafer of semiconductor following the processing of the wafer. The dicing process may be accomplished by scribing and breaking, by mechanical sawing (normally with a machine called a dicing saw), or by laser cutting. All methods of wafer dicing are typically automated to ensure precision and accuracy. Following the dicing process, the individual silicon chips are typically joined to chip carriers and encapsulated, which are then suitable for use in building electronic devices such as computers.
During dicing, wafers are typically mounted on dicing tape which has a sticky backing that holds the wafer on a thin sheet metal frame. Dicing tape has different properties depending on the dicing application. UltraViolet (UV) curable tapes are used for smaller sizes and non-UV dicing tape for larger chip sizes. Once a wafer has been diced, the pieces left on the dicing tape are referred to as chips, dice, or dies. These chips will be packaged in a suitable package or placed directly on a printed circuit board substrate as a “bare chip.” The area cut away from a chip is called chip streets, which are typically about 75 micrometers (0.003 inch) wide. Once a wafer has been diced, the chip will stay on the dicing tape until they are extracted by chip handling equipment, such as a chip bonder or chip sorter, later in the electronics assembly process.
The size of the chip left on the tape may range from 35 mm (very large) to 0.1 mm square (very small). The chip created may be any shape generated by straight lines, but they are typically rectangular or square shaped. In some cases, a chip may be in other shapes as well depending on the singulation method used. A full-cut laser dicer has the ability to cut and separate in a variety of shapes.